Dirt Bike Engine
Dirt Bike Engine Parts at JJ Motorsports
Discover a full range of dirt bike engine components for rebuilding or upgrading your performance from JJ Motorsports. From crankshafts to cylinder heads and piston kits, these precision-engineered components ensure reliable performance. For additional upgrades, check out our full selection of off-road dirt bike parts to keep your engine running at peak efficiency on the track or trails.
Shop trusted brands like Wiseco for forged piston kits and K&N for high-flow oil filters. Explore related categories such as Dirt Bike Air and Fuel for intake upgrades or Dirt Bike Exhaust for complete systems.
Browse our in-stock inventory below with same-day shipping and expert support. Questions? Contact us for fitment advice!
- Product
- Qty in Cart
- Quantity
- Price
- Subtotal
-
PROX Piston Rings 02.4124
PROX
$24.95Proper ring sealing directly impacts combustion efficiency, oil consumption, and overall engine longevity. PROX Piston Rings 02.4124 deliver optimized heat transfer and compression sealing, ensuring your engine maintains peak performance across extended...09120654- SKU:
- 09120654
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- BORE SIZE METRIC:
- 48.45 MM - 48.47 MM
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- PAIR
$24.95Qty in Cart: 0Quantity:Price:$24.95Subtotal: -
PROX Piston Rings 02.6012
PROX
$24.95Piston rings are critical to engine performance—they seal combustion pressure, regulate oil consumption, and transfer heat from the piston to the cylinder wall. PROX Piston Rings 02.6012 are engineered to maintain precise tolerances and consistent...09120656- SKU:
- 09120656
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- BORE SIZE METRIC:
- 39.46 MM - 39.48 MM
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- PAIR
$24.95Qty in Cart: 0Quantity:Price:$24.95Subtotal: -
PROX Piston Rings 02.6225
PROX
$49.95Piston rings are the critical interface between your pistons and cylinder walls—they seal combustion pressure, manage blow-by, and transfer heat away from the combustion chamber. PROX Piston Rings 02.6225 deliver the precision engineering needed to...09120657- SKU:
- 09120657
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 53.94 MM - 53.97 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON RING
- UNITS:
- PAIR
$49.95 -
PROX Piston Rings 02.6394
PROX
$49.95Piston rings are critical to engine efficiency—they seal combustion pressure, regulate oil consumption, and manage heat transfer between the piston and cylinder wall. PROX Piston Rings 02.6394 are engineered for optimal sealing and thermal conductivity,...09120662- SKU:
- 09120662
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 71.94 MM - 71.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- PAIR
$49.95Qty in Cart: 0Quantity:Price:$49.95Subtotal: -
PROX Piston Rings 02.6429
PROX
$49.95Piston rings are the unsung heroes of engine sealing—they maintain compression, control oil consumption, and manage heat transfer between the piston and cylinder wall. PROX Piston Rings 02.6429 deliver the precision tolerances and material quality...09120663- SKU:
- 09120663
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- PAIR
- BORE SIZE METRIC:
- 94.95 MM - 94.97 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- STREET
$49.95Qty in Cart: 0Quantity:Price:$49.95Subtotal: -
PROX Crank Bearing and Seal Kit 23.CBS11085
PROX
$59.95A worn or compromised crankshaft bearing and seal assembly will kill your engine's reliability and performance faster than almost any other failure point. This PROX kit delivers OEM-spec replacements that restore your crank to factory tolerances,...09240294- SKU:
- 09240294
- Availability:
- Ships Same Business Day
- Weight:
- 0.92 LBS
- PRODUCT NAME:
- BEARING AND SEAL KIT
- STYLE:
- 2-STROKE
- TYPE:
- BALL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- APPLICATION:
- CRANKSHAFT
$59.95 -
PROX Crank Bearing and Seal Kit 23.CBS12086
PROX
$57.95A failed crank bearing or seal will leave you stranded—and replacement with inferior components compounds the problem. This PROX kit delivers OEM-spec precision engineering, ensuring your crankshaft operates with the durability and reliability you need...09240297- SKU:
- 09240297
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- APPLICATION:
- CRANKSHAFT
- TYPE:
- BALL
- PRODUCT NAME:
- BEARING AND SEAL KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- 2-STROKE
- UNITS:
- KIT
$57.95 -
PROX Crank Bearing and Seal Kit 23.CBS13004
PROX
$109.95A crankshaft rebuild demands precision bearings and seals that meet OEM tolerances—any compromise here directly impacts engine reliability and performance. The PROX 23.CBS13004 kit eliminates the guesswork by delivering factory-spec components in a...09240298- SKU:
- 09240298
- Availability:
- Ships Same Business Day
- Weight:
- 1.10 LBS
- PRODUCT NAME:
- BEARING AND SEAL KIT
- STYLE:
- 4-STROKE
- APPLICATION:
- CRANKSHAFT
- TYPE:
- BALL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$109.95Qty in Cart: 0Quantity:Price:$109.95Subtotal: -
PROX Crank Bearing and Seal Kit 23.CBS13084
PROX
$70.95A complete crank bearing and seal kit is non-negotiable when you're rebuilding or servicing your crankshaft—skimping on these components invites catastrophic failure under load. The PROX 23.CBS13084 delivers OEM-specification precision across all bearing...09240300- SKU:
- 09240300
- Availability:
- Ships Same Business Day
- Weight:
- 1.50 LBS
- APPLICATION:
- CRANKSHAFT
- PRODUCT NAME:
- BEARING AND SEAL KIT
- TYPE:
- BALL
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- 2-STROKE
- UNITS:
- KIT
$70.95 -
PROX Crank Bearing and Seal Kit 23.CBS14002
PROX
$105.95A complete crank bearing and seal kit is essential for any bottom-end rebuild—whether you're restoring an engine to factory specifications or upgrading to maximize reliability under high RPM loads. This PROX kit eliminates the guesswork by providing...09240304- SKU:
- 09240304
- Availability:
- Ships Same Business Day
- Weight:
- 1.40 LBS
- APPLICATION:
- CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- BEARING AND SEAL KIT
- STYLE:
- 4-STROKE
- TYPE:
- BALL
$105.95Qty in Cart: 0Quantity:Price:$105.95Subtotal: -
PROX Crank Bearing and Seal Kit 23.CBS14096
PROX
$85.95A crankshaft is only as reliable as its bearings and seals—neglect either, and you're risking catastrophic engine failure. The PROX Crank Bearing and Seal Kit 23.CBS14096 gives you a complete, OEM-spec replacement solution that restores your crankshaft...09240306- SKU:
- 09240306
- Availability:
- Ships Same Business Day
- Weight:
- 1.75 LBS
- APPLICATION:
- CRANKSHAFT
- PRODUCT NAME:
- BEARING SET
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- STYLE:
- 4-STROKE
- TYPE:
- BALL
$85.95 -
PROX Crank Bearing and Seal Kit 23.CBS21081
PROX
$38.95A properly sealed and supported crankshaft is foundational to reliable engine performance and longevity. This PROX Crank Bearing and Seal Kit delivers OEM-specification components, eliminating the guesswork and risk of mixing incompatible parts during a...09240308- SKU:
- 09240308
- Availability:
- Ships Same Business Day
- Weight:
- 0.42 LBS
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- 2-STROKE
- UNITS:
- KIT
- APPLICATION:
- CRANKSHAFT
- TYPE:
- BALL
- PRODUCT NAME:
- BEARING AND SEAL KIT
$38.95 -
PROX Crank Bearing and Seal Kit 23.CBS21082
PROX
$33.95A complete crank bearing and seal kit is essential for any bottom-end rebuild—it ensures proper clearances, reduces friction, and extends crankshaft life. Whether you're restoring an engine to OEM spec or upgrading with a Pro X crank, this kit gives you...09240309- SKU:
- 09240309
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- 2-STROKE
- UNITS:
- KIT
- PRODUCT NAME:
- BEARING AND SEAL KIT
- APPLICATION:
- CRANKSHAFT
- TYPE:
- BALL
$33.95Qty in Cart: 0Quantity:Price:$33.95Subtotal: -
PROX Crank Bearing and Seal Kit 23.CBS21083
PROX
$59.95A crankshaft rebuild demands precision—substandard bearings and seals invite catastrophic failure and costly downtime. This PROX kit delivers OEM-exact specifications for reliable durability, whether you're running a stock bottom end or pairing it with a...09240310- SKU:
- 09240310
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- APPLICATION:
- CRANKSHAFT
- STYLE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- BEARING AND SEAL KIT
- TYPE:
- BALL
$59.95 -
PROX Crank Bearing and Seal Kit 23.CBS21093
PROX
$36.95A compromised crankshaft bearing or seal can cascade into catastrophic engine failure—and downtime you can't afford. This PROX kit delivers OEM-spec replacements for both bearings and seals, ensuring your crank runs true and your engine stays sealed...09240311- SKU:
- 09240311
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- APPLICATION:
- CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- STYLE:
- 2-STROKE
- PRODUCT NAME:
- BEARING AND SEAL KIT
- TYPE:
- BALL
$36.95 -
PROX Crank Bearing and Seal Kit 23.CBS22079
PROX
$39.95A crankshaft rebuild demands precision—any wear in the bearing surfaces or seal integrity compromises engine reliability and performance. The PROX Crank Bearing and Seal Kit 23.CBS22079 delivers OEM-specification components that restore your crankshaft...09240314- SKU:
- 09240314
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- 2-STROKE
- UNITS:
- KIT
- PRODUCT NAME:
- BEARING AND SEAL KIT
- APPLICATION:
- CRANKSHAFT
- TYPE:
- BALL
$39.95 -
PROX Crank Bearing and Seal Kit 23.CBS22080
PROX
$38.95A failed crank bearing or seal will sideline your engine faster than any mechanical failure—this PROX kit gives you everything needed for a complete, reliable rebuild without sourcing multiple components separately. Whether you're refreshing an OEM...09240315- SKU:
- 09240315
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- 2-STROKE
- UNITS:
- KIT
- APPLICATION:
- CRANKSHAFT
- TYPE:
- BALL
- PRODUCT NAME:
- BEARING AND SEAL KIT
$38.95 -
PROX Crank Bearing and Seal Kit 23.CBS22086
PROX
$70.95A worn crank bearing and seal kit compromises engine reliability and performance—exactly what you can't afford during a rebuild or overhaul. This PROX kit delivers OEM-specification components engineered to restore your crankshaft to factory tolerances,...09240316- SKU:
- 09240316
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- UNITS:
- KIT
- STYLE:
- 2-STROKE
- APPLICATION:
- CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- BEARING AND SEAL KIT
- TYPE:
- BALL
$70.95 -
PROX Crank Bearing and Seal Kit 23.CBS22098
PROX
$70.95A quality crank bearing and seal kit is non-negotiable for engine reliability and longevity—especially when you're pushing your machine to its limits. The PROX 23.CBS22098 delivers OEM-spec components that restore your crankshaft assembly to factory...09240318- SKU:
- 09240318
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- PRODUCT NAME:
- BEARING AND SEAL KIT
- STYLE:
- 2-STROKE
- TYPE:
- BALL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- APPLICATION:
- CRANKSHAFT
$70.95 -
PROX Crank Bearing and Seal Kit 23.CBS23001
PROX
$70.95A worn crankshaft bearing or seal failure will sideline your engine and derail your season. This PROX kit delivers all the bearings and seals you need to restore your crank to OEM specifications without guesswork or compatibility issues. Whether you're...09240320- SKU:
- 09240320
- Availability:
- Ships Same Business Day
- Weight:
- 1.55 LBS
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- 2-STROKE
- UNITS:
- KIT
- APPLICATION:
- CRANKSHAFT
- TYPE:
- BALL
- PRODUCT NAME:
- BEARING AND SEAL KIT
$70.95
